Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube insert...Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube inserted with rotor-assembled strand was conducted and the flow characteristics on transverse section and longitudinal section were analyzed.The results showed that swirling flow was produced in the tube inserted with rotors and it was particularly strong within the swing diameter of the rotor on the section that contains the rotor;the average turbulence intensity and the radial velocity were improved notably; the velocity vectors on the longitudinal section remained along the direction of a straight line; both the swirling flow and average turbulence intensity were higher for the rotor with three blades than for the rotor with two blades except that the radial velocity was approximate, but they were all reduced by enlarging the lead of the rotor.Characterization of the flow patterns in a circular tube contributes to understanding the heat transfer efficiency and scale inhibition performance of the rotor-assembled strand and provides guidance for its application.展开更多
This paper describes a CAD compatible software which can conduct model measurementand analysis on a dedicated computer system.This system which can provide modal testing andanalysis capability is also demonstrated bri...This paper describes a CAD compatible software which can conduct model measurementand analysis on a dedicated computer system.This system which can provide modal testing andanalysis capability is also demonstrated briefly.It addresses four main tasks:(1)modal testingand data acquisition,(2)data analysis and correlation,(3)output of modal analysis results,(4)predictions of modal parameters using Structural Dynamic Modification (SDM)software.展开更多
The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of ...The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of single disc and combined discs on rotor dynamic characteristics are firstly implemented in respect of the dispersity of rotor initial unbalance.It is found that the most important factors contributing to rotor vibration are the unbalances of the first stage compressor disc and the second stage turbine disc.However,reducing the mass of two discs conflicts with the control of the whole gas generator rotor balance resulting from the unbalance increase of single components.Thus,we further analyze the key control factors of affecting rotor initial unbalance,and give the strict control measures of centrifugal impeller runout in the assembly process by adjusting the angle of central tie rod axis.The purpose of this measures to make the assembly process simpler and more effective for timely controlling rotor initial unbalance.The efforts of this study validate that the proposed method is workable for the rotor tightened by a central tie rod and possesses the significant meaning of practical application in engineering.展开更多
The assembling of a coating of time-resolved fluorescent chelator BSPDA （ abbreviated for 4, 7-bis （ sulfhydrylphenyl）-1, 10-phenanthroline-2, 9-dicarboxylic acid） onto a nano-gold layer was demonstrated. First, B...The assembling of a coating of time-resolved fluorescent chelator BSPDA （ abbreviated for 4, 7-bis （ sulfhydrylphenyl）-1, 10-phenanthroline-2, 9-dicarboxylic acid） onto a nano-gold layer was demonstrated. First, BSPDA was synthesized by simple procedures, and then an approach was developed to immobilize BSPDA onto the nano-gold layer deposited on a silane modified glass substrate, whereby europium ion （Ⅲ, Eu^3＋ ） was captured and released owing to the interactive process of complexation and dissociation between BSPDA functionalized coating and Eu^3＋ solution. The fluorescence spectra and related lifetimes were determined. Also, the BSPDA functionalized coating＇s specific complexation with Eu^3＋ on the BSPDA assembly layer and the nonspecific adsorption of Eu^3＋ on the nano-gold layer were compared. These results allowed a selective complexation of Eu^3＋ by assembling a BSPDA chelating layer on the nano-gold layer; thus, a tunable time-resolved fluorescent layer was covalently attached, The results of the nanoparticle assembling and probing （or labeling） processes to specific bio-systems were very interesting and had significant implications to time-resolved-fluorescence-based detection on biosensor surfaces such as DNA chip and to arrayed light display devices.展开更多
Well-defined Si- and Ti-MCM-41 mesoporous molecular sieves were synthesized in high yields through the halogen anion mediated S(+)X(-)I(+) assembly in the presence of cetylpyridinium bromide as template. The spectrosc...Well-defined Si- and Ti-MCM-41 mesoporous molecular sieves were synthesized in high yields through the halogen anion mediated S(+)X(-)I(+) assembly in the presence of cetylpyridinium bromide as template. The spectroscopy characterization of the as-synthesized samples confirmed that Ti (IV) could be isolated in the lattice positions of the MCM-41 mesostructure by this method.展开更多
The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchic...The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchical self-assembly of atomically precise gold nanoclusters(Au NCs)with molecular rotor-based ligands(MRL),featuring a double-layer surface.Compared to two other types of monolayer-protected(MLP)Au NCs,the significantly reduced surface density for MRL Au NCs profoundly influences their assembly behavior within the lattice.Furthermore,the long length of rotor-based ligands and the rotational freedom of the phenyl-rings of rotor-based ligands also facilitate the assembly of NCs.Our works elucidate the hierarchical assembly on a precise scale,suggesting that the rotor-based ligand’s strategy offers promising potential for designing well-defined and more complex structures in supercrystals.展开更多
Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor,based on the fluid structure coupling method,the temperature distribution of motor under three cooling scheme...Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor,based on the fluid structure coupling method,the temperature distribution of motor under three cooling schemes of air cooling and water cooling are calculated respectively.For the structure I air cooling system,the influence of different number of heat sink on the maximum temperature rise and pressure drop of fluid channel is analyzed,and the parameters of heat sink are optimized.For the structure II air cooling system,the influence of setting fillet at the turn back of the fluid channel on the head loss in the fluid domain of the motor is analyzed,and the influence of different fillet radius on the head loss and the maximum temperature rise in the fluid domain is obtained.For the structure II water cooling system,the influence of different water flow speed on the maximum temperature rise of the motor is analyzed,and the influence of different assembly clearance of modular stator teeth and yoke on the maximum temperature rise of the motor is analyzed.The cooling effect and temperature rise distribution characteristics of the three cooling schemes are compared and analyzed.Finally,a water-cooled prototype is manufactured,and the temperature rise experiment is carried out,and the influence of the thermal deformation of fluid channel,stator yoke and stator teeth on the maximum temperature of the motor is analyzed.The results show that the calculated temperature field after considering the thermal deformation is closer to the experimental value,which verifies the accuracy of the calculation results,It also provides a reference for the selection and design of the cooling structure of the same type of PMSM electric roller.展开更多
In this paper the formulation of finite element analysis for frame casing problems of theharmonic type is described. Attention is paid to the OE spinning rotor bearing assembly (RBA)’ sdynamic model, whose harmonic p...In this paper the formulation of finite element analysis for frame casing problems of theharmonic type is described. Attention is paid to the OE spinning rotor bearing assembly (RBA)’ sdynamic model, whose harmonic parameters, such as natural frequencies and modal shapes, aresolved by means of structural analysis program using personal computer, i.e. SAP84 software. Ac-cording to orthogonal factorial design table (OFDT), the predominant sensitive influential factors(PSIF) of RBA are determined.展开更多
Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe...Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.展开更多
Tip clearances of multistage rotors and stators greatly affect aero-engines’ aerodynamic efficiency, stability and safety. The inevitable machining and assembly errors, as well as the complicated error propagation me...Tip clearances of multistage rotors and stators greatly affect aero-engines’ aerodynamic efficiency, stability and safety. The inevitable machining and assembly errors, as well as the complicated error propagation mechanism, cause overproof or non-uniform tip clearances. However, it is generally accepted that tip clearances are difficult to predict, even under assembly state. In this paper, a tip clearance prediction model is proposed based on measured error data. Some 3 D error propagation sub-models, regarding rotors, supports and casings, are built and combined. The complex error coupling relationship is uncovered using mathematical methods. Rotor and stator tip clearances are predicted and analyzed in different phase angles. The maximum, minimum and average tip clearances can be calculated. The proposed model is implemented by a computer program,and a case study illustrates its performance and verifies its feasibility. The results can be referred by engineers in assembly quality judgement and decision-making.展开更多
基金Supported by the National Natural Science Foundation of China(51576012)
文摘Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube inserted with rotor-assembled strand was conducted and the flow characteristics on transverse section and longitudinal section were analyzed.The results showed that swirling flow was produced in the tube inserted with rotors and it was particularly strong within the swing diameter of the rotor on the section that contains the rotor;the average turbulence intensity and the radial velocity were improved notably; the velocity vectors on the longitudinal section remained along the direction of a straight line; both the swirling flow and average turbulence intensity were higher for the rotor with three blades than for the rotor with two blades except that the radial velocity was approximate, but they were all reduced by enlarging the lead of the rotor.Characterization of the flow patterns in a circular tube contributes to understanding the heat transfer efficiency and scale inhibition performance of the rotor-assembled strand and provides guidance for its application.
文摘This paper describes a CAD compatible software which can conduct model measurementand analysis on a dedicated computer system.This system which can provide modal testing andanalysis capability is also demonstrated briefly.It addresses four main tasks:(1)modal testingand data acquisition,(2)data analysis and correlation,(3)output of modal analysis results,(4)predictions of modal parameters using Structural Dynamic Modification (SDM)software.
文摘The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of single disc and combined discs on rotor dynamic characteristics are firstly implemented in respect of the dispersity of rotor initial unbalance.It is found that the most important factors contributing to rotor vibration are the unbalances of the first stage compressor disc and the second stage turbine disc.However,reducing the mass of two discs conflicts with the control of the whole gas generator rotor balance resulting from the unbalance increase of single components.Thus,we further analyze the key control factors of affecting rotor initial unbalance,and give the strict control measures of centrifugal impeller runout in the assembly process by adjusting the angle of central tie rod axis.The purpose of this measures to make the assembly process simpler and more effective for timely controlling rotor initial unbalance.The efforts of this study validate that the proposed method is workable for the rotor tightened by a central tie rod and possesses the significant meaning of practical application in engineering.
基金Project supported by the National Natural Science Foundation of China (20505020) the Natural Science Foundation ofGuangdong Province (06300086) +2 种基金 China Postdoctoral Science Foundation (20060390202) Scientific Research Fund ofHunan Provincial Education Department (05C508) Skeleton Youth Faculty Programof Hunan Higher Educational School
文摘The assembling of a coating of time-resolved fluorescent chelator BSPDA （ abbreviated for 4, 7-bis （ sulfhydrylphenyl）-1, 10-phenanthroline-2, 9-dicarboxylic acid） onto a nano-gold layer was demonstrated. First, BSPDA was synthesized by simple procedures, and then an approach was developed to immobilize BSPDA onto the nano-gold layer deposited on a silane modified glass substrate, whereby europium ion （Ⅲ, Eu^3＋ ） was captured and released owing to the interactive process of complexation and dissociation between BSPDA functionalized coating and Eu^3＋ solution. The fluorescence spectra and related lifetimes were determined. Also, the BSPDA functionalized coating＇s specific complexation with Eu^3＋ on the BSPDA assembly layer and the nonspecific adsorption of Eu^3＋ on the nano-gold layer were compared. These results allowed a selective complexation of Eu^3＋ by assembling a BSPDA chelating layer on the nano-gold layer; thus, a tunable time-resolved fluorescent layer was covalently attached, The results of the nanoparticle assembling and probing （or labeling） processes to specific bio-systems were very interesting and had significant implications to time-resolved-fluorescence-based detection on biosensor surfaces such as DNA chip and to arrayed light display devices.
文摘Well-defined Si- and Ti-MCM-41 mesoporous molecular sieves were synthesized in high yields through the halogen anion mediated S(+)X(-)I(+) assembly in the presence of cetylpyridinium bromide as template. The spectroscopy characterization of the as-synthesized samples confirmed that Ti (IV) could be isolated in the lattice positions of the MCM-41 mesostructure by this method.
基金supported by the National Key R&D Program of China(No.2023YFC3404200)the National Natural Science Foundation of China(Nos.21974147,22325406)+1 种基金the 2022 Shanghai“Science and Technology Innovation Action Plan”Fundamental Research Project,China(No.22JC1401203)the Science Foundation of the Shanghai Municipal Science and Technology Commission,China(No.21dz2210100).
文摘The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchical self-assembly of atomically precise gold nanoclusters(Au NCs)with molecular rotor-based ligands(MRL),featuring a double-layer surface.Compared to two other types of monolayer-protected(MLP)Au NCs,the significantly reduced surface density for MRL Au NCs profoundly influences their assembly behavior within the lattice.Furthermore,the long length of rotor-based ligands and the rotational freedom of the phenyl-rings of rotor-based ligands also facilitate the assembly of NCs.Our works elucidate the hierarchical assembly on a precise scale,suggesting that the rotor-based ligand’s strategy offers promising potential for designing well-defined and more complex structures in supercrystals.
基金This work has been supported by the National Natural Science Foundation of China(51907129)Project Supported by Department of Science and Technology of Liaoning Province(2021-MS-236).
文摘Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor,based on the fluid structure coupling method,the temperature distribution of motor under three cooling schemes of air cooling and water cooling are calculated respectively.For the structure I air cooling system,the influence of different number of heat sink on the maximum temperature rise and pressure drop of fluid channel is analyzed,and the parameters of heat sink are optimized.For the structure II air cooling system,the influence of setting fillet at the turn back of the fluid channel on the head loss in the fluid domain of the motor is analyzed,and the influence of different fillet radius on the head loss and the maximum temperature rise in the fluid domain is obtained.For the structure II water cooling system,the influence of different water flow speed on the maximum temperature rise of the motor is analyzed,and the influence of different assembly clearance of modular stator teeth and yoke on the maximum temperature rise of the motor is analyzed.The cooling effect and temperature rise distribution characteristics of the three cooling schemes are compared and analyzed.Finally,a water-cooled prototype is manufactured,and the temperature rise experiment is carried out,and the influence of the thermal deformation of fluid channel,stator yoke and stator teeth on the maximum temperature of the motor is analyzed.The results show that the calculated temperature field after considering the thermal deformation is closer to the experimental value,which verifies the accuracy of the calculation results,It also provides a reference for the selection and design of the cooling structure of the same type of PMSM electric roller.
文摘In this paper the formulation of finite element analysis for frame casing problems of theharmonic type is described. Attention is paid to the OE spinning rotor bearing assembly (RBA)’ sdynamic model, whose harmonic parameters, such as natural frequencies and modal shapes, aresolved by means of structural analysis program using personal computer, i.e. SAP84 software. Ac-cording to orthogonal factorial design table (OFDT), the predominant sensitive influential factors(PSIF) of RBA are determined.
文摘Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.
基金co-supported by the Equipment Pre-Research Foundation (No. 61409230204)the National Basic Research Project (No. 2017-VII-0010-0104)+2 种基金the Defense Industrial Technology Development Program (No. XXXX2018213A001)the National Natural Science Foundation of China(No. 51875475)the Key Development Program of Shaanxi Province (Nos. 2018ZDXM-GY-068 and 2016KTZDGY4-02)。
文摘Tip clearances of multistage rotors and stators greatly affect aero-engines’ aerodynamic efficiency, stability and safety. The inevitable machining and assembly errors, as well as the complicated error propagation mechanism, cause overproof or non-uniform tip clearances. However, it is generally accepted that tip clearances are difficult to predict, even under assembly state. In this paper, a tip clearance prediction model is proposed based on measured error data. Some 3 D error propagation sub-models, regarding rotors, supports and casings, are built and combined. The complex error coupling relationship is uncovered using mathematical methods. Rotor and stator tip clearances are predicted and analyzed in different phase angles. The maximum, minimum and average tip clearances can be calculated. The proposed model is implemented by a computer program,and a case study illustrates its performance and verifies its feasibility. The results can be referred by engineers in assembly quality judgement and decision-making.
